Bicycle frame



FIG. 1 is a top, rear, and left side perspective view of a bicycle frame embodying our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines in the drawings illustrate portions of the bicycle frame and environmental bicycle structures that form no part of the claimed design. 

CLAIM The ornamental design for a bicycle frame, as shown and described. 